In general, a refrigerator includes an insulation box manufactured by charging a foamed insulation such as foamed polyurethane between an outer box made of a steel plate and an inner box made of a rigid synthetic resin by field foaming. The insulation box is partitioned off into storing chambers such as a freezing chamber, a refrigerating chamber and a vegetable chamber.
For example, a mechanical chamber is installed at the lower portion of the insulation box, and a compressor, a condenser and a ventilator for condenser which form a cooling device are installed therein. A cooler forming a freezing cycle with the cooling device is vertically installed on the rear surfaces of the storing chambers, and a ventilator for cooler is installed at the upper portion of the cooler. A partitioning plate is installed at the front portions of the cooler and the ventilator, and cool air ducts are installed between the partitioning plate and the rear wall of the insulation box.
When the compressor and the ventilator of the cooling device are operated, cool air cooled in the cool air ducts is discharged into the storing chambers. Among the storing chambers, the freezing chamber is cooled to a freezing temperature of −20° C., and the refrigerating chamber is maintained at a refrigerating temperature of +5° C. In addition, foods needing moisture such as vegetables are preserved in the vegetable chamber at an appropriate temperature.
For this, the temperatures inside the freezing chamber, the refrigerating chamber and the vegetable chamber are sensed, and the sensed temperatures are compared with preset reference temperatures. If the sensed temperatures are higher than the reference temperatures, the freezing cycle and the ventilator are driven at the same time for supplying cool air.
It is thus necessary to restrict respiration and transpiration of the foods (especially, vegetables) to maintain the freshness of the foods. As described above, the conventional refrigerator only controls the temperatures to maintain the freshness of the foods. Except for some foods experiencing low temperature lesion such as vegetables, respiration is restricted at a low temperature and transpiration is prevented at high humidity in many foods. However, the temperature control does not satisfy the user in respect of the freshness of the foods. Also, in the conventional refrigerator, the user must individually find appropriate keeping methods of each food. Even if the user finds the appropriate keeping methods of each food, he/she cannot acquire information on which parts of the storing chambers can minimize reduction of the freshness and nutrition of the foods and keep the foods for an extended period of time.